US Patent 7439786 Power amplification circuits

A power amplification circuit includes first and second clock signal generating portions operable to produce, respectively, first and second clock signals different in frequency from each other; first and second PWM signal generating portions operable to produce first and second PWM signals based on first and second input signals using the first and second clock signals, respectively; a first switching amplifier operable to perform a switching operation in response to the first PWM signal to subject the first PWM signal to power amplification to produce a first output signal and to supply the first output signal to a first circuit load; and a second switching amplifier operable to perform a switching operation in response to the second PWM signal to subject the second PWM signal to power amplification to produce a second output signal and to supply the second output signal to a second circuit load.